A TG–FTIR investigation to the catalytic effect of mineral matrix in oil shale on the pyrolysis and combustion of kerogen

A demineralized Huadian oil shale sample, p-kerogen, is obtained through HCl&HF treatment. The XRD test for oil shale identifies the minerals in it. The catalytic effect of minerals in oil shale on the pyrolysis and combustion of kerogen is investigated through the TG–FTIR test to original oil shale and p-kerogen. The resultant effect of all minerals in oil shale promotes the decomposition and release of the organic matter in the sample during the pyrolysis. The promoting effect of minerals on the oxidation of kerogen expresses in two aspects: on the one hand, the catalytic effect of minerals makes more organic matter oxidized in the first oxidation stage; on the other hand, the presence of inorganic framework creates the additional porosity in oil shale after the first oxidation stage, which significantly decreases the resistance of oxygen diffusing into the inner of sample particles. Part of the pyrite in the sample will be converted into new organic sulfur compounds in the absence of other minerals while most of pyritic sulfurs are oxidized into SO2 directly and then deposited within sample particles in the presence of minerals during the combustion.